In general, sound is initially recorded by a microphone and then is reproduced by speakers. When sound data is reproduced by speakers, treble sound and bass sound can be separated to output, which enables a user to preferably adjust volumes of treble sound and bass sound.
However, as shown in FIG. 1, the conventional speakers has employed a 2-way structure in which treble sound (a high-frequency speaker; 20) and bass sound (a low-frequency speaker; 10) are reproduced in separate channels. This 2-way structure has an advantage that volumes of treble sound and bass sound may be selectly adjusted. However, because treble and bass sounds are reproduced in separate channels, a single tone is output in different position. Therefore, this structure has disadvantage that sound reproduction is inaccurate.
For example, an orchestra performance may be recorded by a single microphone. Because the recording is done in a single channel (i.e., a single position of recording), its reproduction may preferably provide a natural sense of presence when the reproduced sound is output via a single channel (i.e., a single position of sound output). However, in the 2-way structure, the sound reproduction is inaccurate by sound output in two channels, which renders the sense of presence be poor.
In order to overcome these disadvantages, there is disclosed a coaxial speaker technology in which a high-frequency speaker for treble sound and a low-frequency speaker for bass sound may be incorporated in a coaxial line.
The conventional coaxial speaker adopts special mechanical design of different structures other than typical 2-way speakers because the high-frequency and low-frequency speakers are connected to interoperate each other. Accordingly, the conventional coaxial speaker has disadvantage of high production costs. In addition, the conventional coaxial speaker has further disadvantage of poor extra-bass reproduction because the low-frequency speaker which vibrates with outputting bass sound is under the influence of high-frequency speaker in a coaxial line.
The list of reference documents for the present invention may be as below.
1. Coexial speaker (KR patent application No. 10-2007-0080525)
2. Coexial speaker (KR patent application No. 10-2007-0035577)
3. Speaker device (US patent publication No. US 2005/0276436 A1)
4. Automotive loudspeaker having variable speaker orientation and particular electrical connections (U.S. Pat. No. 4,365,114 B)
5. Speaker device (US patent publication No. US 2005/0276436 A)